bug#27437: Source downloader accepts X.509 certificate for incorrect domain

[ludo@gnu.org (Ludovic Courtès)]

Leo Famulari <leo@famulari.name> skribis:

> On Thu, Jun 22, 2017 at 11:33:31AM -0400, Mark H Weaver wrote:
>> ludo@gnu.org (Ludovic Courtès) writes:
>> > IOW, since we’re checking the integrity of the tarball anyway, and we
>> > assume developers checked its authenticity when writing the recipe, then
>> > who cares whether downloads.xiph.org has a valid certificate?
>> >
>> > Conversely, ‘guix download’ always checks certificates by default.
>> >
>> > Does it make sense?
>> 
>> Yes, and I agree with this behavior.  However, it should be noted that
>> this will reduce the security of a bad practice that I suspect is
>> sometimes used by people when updating packages, namely to update the
>> version number, try building it, and then copy the hash from the error
>> message to the package.
>
> Yeah, that's a bad habit and I warn people against it whenever it comes
> up :/

Agreed.

That said, if we look at our updaters:

--8<---------------cut here---------------start------------->8---
$ guix refresh --list-updaters 
Available updaters:

  - cpan: Updater for CPAN packages (9.2% coverage)
  - cran: Updater for CRAN packages (4.0% coverage)
  - bioconductor: Updater for Bioconductor packages (1.2% coverage)
  - crates: Updater for crates.io packages (.0% coverage)
  - elpa: Updater for ELPA packages (.3% coverage)
  - gem: Updater for RubyGem packages (2.5% coverage)
  - github: Updater for GitHub packages (10.5% coverage)
  - hackage: Updater for Hackage packages (5.2% coverage)
  - pypi: Updater for PyPI packages (17.6% coverage)
  - stackage: Updater for Stackage LTS packages (5.2% coverage)
  - kernel.org: Updater for packages hosted on kernel.org (.5% coverage)
  - gnome: Updater for GNOME packages (2.9% coverage)
  - xorg: Updater for X.org packages (3.2% coverage)
  - gnu: Updater for GNU packages (5.6% coverage)
  - kde: Updater for KDE packages (1.3% coverage)

69.0% of the packages are covered by these updaters.
--8<---------------cut here---------------end--------------->8---

I think only GNU and kernel.org provide signatures, which represents 6%
of our packages.  Of the 30% that do not have an updater, surely some
have digital signatures, but we’re probably still below 10%.  The
situation is bad in general…

Ludo’.